The invention relates to fluid sensors and particularly to microsensors. More particularly it pertains to housing for such sensors. Microsensors have one vexing packaging problem. Their space-saving and cost-saving smallness in surface area and membrane thickness make them vulnerable to occasional impacts with particles. The solid particles may destroy the gas-sensitive membrane of the sensor or change its heat transfer features with just a thin coat of sticky particles. The liquid ones may have the same effect as the small solids, if a residue stays after re-evaporation.
These problems continue to be of concern in relation to the development of microsensors of fluid vapor as needed for control or recovery operations of such vapors. The cause of the problem is the need to satisfy two competing goals which are to achieve a short response time (e.g., one to three seconds or less) and a service life of about ten years. Resolving the fundamental approach to sensing fluid properties is an important and essential step. But at least of equal importance is the design of a sensor housing or package, which will enable the sensor to perform its function rapidly, sensitively and reliably, even in harsh environments. The problem is that the filters and baffles one would provide to insure protection for long and reliable sensor service are the same that would increase response time to unacceptable levels. The present invention provides a solution and tradeoff between speed of response and sensor protection.